The Known Good Updated 29 Jul 2026
OpenAI: GPT-5.4 vs Z.ai: GLM 5.1 ·OpenAI vs Z.ai

OpenAI: GPT-5.4 vs Z.ai: GLM 5.1 — head-to-head comparison

OpenAI: GPT-5.4 profile Z.ai: GLM 5.1 profile All comparisons
OpenAI: GPT-5.4 — OpenAI
Quality
#10 of 62
90based on 5 of 7 evaluations
Known Good Index
Speed
#90 of 317
68.0
Output tokens per second
Price
#328 of 370
$5.62
Blended per 1M tokens
In $2.50 · Out $15.00
Cache hit price
#192 of 238
$0.25
per 1M tokens (−90%)
Context
#17 of 375
1.05M
tokens (~1,600 pages)
Z.ai: GLM 5.1 — Z.ai
Quality
#12 of 62
88based on 3 of 7 evaluations
Known Good Index
Speed
#138 of 317
53.0
Output tokens per second
Price
#235 of 370
$1.48
Blended per 1M tokens
In $0.97 · Out $3.04
Cache hit price
#162 of 238
$0.18
per 1M tokens (−81%)
Context
#222 of 375
205k
tokens (~300 pages)
Summary

On the Known Good Index, OpenAI: GPT-5.4 scores 90 and Z.ai: GLM 5.1 scores 88 — a 2-point lead for OpenAI: GPT-5.4. They share 3 published evaluations, with OpenAI: GPT-5.4 ahead on 3 and Z.ai: GLM 5.1 ahead on 0.

Blended pricing is $5.62 per 1M tokens for OpenAI: GPT-5.4 and $1.48 for Z.ai: GLM 5.1 — Z.ai: GLM 5.1 is about 3.8× cheaper.

Throughput is 68 tokens per second for OpenAI: GPT-5.4 and 53 for Z.ai: GLM 5.1, with time to first token at 2.5s and 1.8s. OpenAI: GPT-5.4 accepts 1.05M tokens of context against 205k.

OpenAI: GPT-5.4 is proprietary; Z.ai: GLM 5.1 is proprietary. 21 tracked hosts serve one or both.

Generated from tracked data on 29 Jul 2026 · how these comparisons are computed →

At a glance
MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Known Good Index 90 based on 5 of 7 evaluations 88 based on 3 of 7 evaluations
Blended $/1M $5.62 $1.48
Output tok/s 68 53
Context window 1.05M 205k
Providers 2 19
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Quality

Known Good Index and the capability indices, side by side

Index scores

Each index is min-max normalised across tracked models and scaled 0–100 from published evaluations. We do not run these evaluations.

MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Known Good Index 90 88
Coding Index 89
Mathematics Index 98 92
Reasoning Index 88
Agentic Index 89 82
Openness Index 5 5
The Known Good

Quality Breakdown

Every evaluation both models report a published score for

Evaluations both models report

Bar = OpenAI: GPT-5.4 · marker = Z.ai: GLM 5.1 · scores ingested from Epoch AI (CC-BY 4.0)

GPQA Diamond93 / 85
Mock AIME 2024–2598 / 92
SWE-bench Verified77 / 74

Right-hand figures read OpenAI: GPT-5.4 / Z.ai: GLM 5.1. OpenAI: GPT-5.4 leads on 3 of 3, Z.ai: GLM 5.1 on 0.

The Known Good

Arena Elo

Human preference rating from blind pairwise votes

Arena ratings

Elo from blind pairwise votes, ingested from Arena. Higher is better.

MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Text Arena 1,452 1,465
Text Arena (style controlled) 1,465 1,469
The Known Good

Price & Cost

Published API pricing by token type

Published pricing

USD per 1M tokens. Blended is a 3:1 input:output mix. Live from OpenRouter, cross-checked against models.dev. Lower is better.

MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Input $/1M $2.50 $0.97
Output $/1M $15.00 $3.04
Blended $/1M $5.62 $1.48
Cache read $/1M $0.250 $0.179
The Known Good
We publish blended price rather than cost-per-task. Cost-per-task requires token counts from an evaluation suite we do not run. Blended price is computed from published rates and is fully reproducible — see the pricing methodology.

Context Window

Maximum input accepted and maximum output emitted

Context and output limits

Provider-declared limits, from metadata via models.dev and OpenRouter. Higher is better.

MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Context window 1.05M 205k
Max output tokens 128k 128k
The Known Good

Speed & Latency

Median throughput and time to first token across hosting providers

Output speedTime to first token
Throughput and latency

Medians across all tracked providers, derived from OpenRouter endpoint telemetry.

MetricOpenAI: GPT-5.4Z.ai: GLM 5.1
Output tokens/s 68 53
Time to first token 2.5s 1.8s
The Known Good

Providers

Which hosts serve each model, and at what price and speed

21 hosts
Full provider benchmarks →
Provider OpenAI: GPT-5.4 blendedOpenAI: GPT-5.4 tok/s Z.ai: GLM 5.1 blendedZ.ai: GLM 5.1 tok/s
Azure · first party $5.62 59
OpenAI · first party $2.81 59
CoreWeave $2.15 146
Wafer $1.55 87
GMICloud $1.50 66
Parasail $2.15 66
Venice $2.37 64
DeepInfra $1.66 62
Friendli $2.15 59
SiliconFlow $1.83 57
Crusoe $2.00 54
Novita $2.13 51
StreamLake $1.48 43
Baidu · first party $1.46 42
Phala $1.96 42
Z.AI · first party $2.15 42
Chutes $1.50 41
Nebius $2.15 29
AtlasCloud $1.94 27
DigitalOcean $1.81 20
Fireworks $2.15

Per-host pricing and telemetry from OpenRouter. A dash means that host does not serve that model.

The Known Good
Sources for this page
Pricing & providers — OpenRouter Metadata — models.dev Benchmarks — Epoch AI (CC-BY 4.0)Elo — Arena Full attribution →